Health expenditures for the roughly 9 million dually-eligible beneficiaries in the U.S. are now reaching a quarter of a trillion dollars in 2010. However, the current financial scheme for duals creates incentives to shift cost between Medicare and Medicaid, often hindering efforts to improve quality of care and potentially limiting access for this vulnerable sub population. The main purpose of this proposed study is to compare the use of medical services provided under an integrated managed care system and relate outcomes for dually-eligible beneficiaries with the controls who participate in traditional fee-for-service programs. We will examine this by evaluating MassHealth Senior Care Options (SCO), an integrated Medicare and Medicaid managed care program that offers the full collection of services provided by both programs for dual-eligible beneficiaries in Massachusetts. The specific aims are: Aim 1: To estimate the effects of participation in Senior Care Options on medical services utilization, with measures of inpatient, ambulatory and post-acute care compared to duals in Medicare FFS. Aim 2: To determine whether participation in Senior Care Options is associated with lower mortality and reduced 30 day re-hospitalization. The proposed study will examine the effects with a relatively long period of program observation (2001-2008) and rigorous econometric tools that mitigate selection bias. As an identification strategy, multiple econometric methods, including difference-in-difference-in-differences (DDD), will be utilized. Cross-sectional regression and simple difference-in-differences approaches leave estimates vulnerable to selection bias due to comparing two systemically different groups. A DDD model allows the effect of treatment to be assessed with the inclusion of an additional comparison group (non-dual Medicare FFS beneficiaries) that should not be affected by the implementation of SCO. The DDD specification will control for confounding arising from changes in health status of duals across counties which have nothing to do with SCO availability. Given the current economic environment and the complexity of care this growing population requires, the proposed analysis will provide evidence of the potential gains associated with better coordination of Medicaid and Medicare benefits for the dually-eligible. The study will address a very timely and important issue of concern for policymakers. The results will provide insights leading to higher quality of care provided more efficiently for dually-eligible beneficiaries for a wide range of services. PUBLIC HEALTH RELEVANCE: Dually-eligible beneficiaries, those who qualify for both Medicare and Medicaid, are generally sicker with fewer financial resources compared to other Medicare enrollees. They have a greater need for comprehensive health services, but often encounter a lack of continuity of care, inadequate administrative coordination between Medicare and Medicaid, no clear accountability for needed care, and a lack of smooth transitions between services. The findings from this project will demonstrate the influence of coordinating Medicare and Medicaid benefits through an integrated managed care program to promote higher quality of care while providing health services more efficiently for this vulnerable population.